McIlroy finds the bunker short of the green on the 10th and rather than hunting for a birdie, he could have a scramble on to save par. We shall see...
Moments earlier, Rickie Fowler did conjure up a birdie on the 10th to go to 10 under and should McIlroy drop a shot, the American will be breathing down his neck.
McIlroy escapes from the bunker competently enough and although he cannot sink a 15 footer for birdie, he does make par and on balance, he has to be happy as he leaves the 10th.
Dark clouds are hovering ominously over Hoylake but the downpour continues to hold off. The bods with their satellites and computers at the Met Office haven't got a clue, have they?
Rickie Fowler is certainly a pugnacious golfer. The American drops in a long putt on the 11th and he's now 11 under and just one shot behind Mr McIlroy.
Sergio Garcia's charge has abated somewhat with pars on the 10th and 11th but the Spaniard is still nine under and a force to be reckoned with.
Darren Clarke is finished and cards a superb five under 67.
McIlroy's putting today has been faultless. He lands his eight footer on the 11th for a birdie and he's 13 under, two clear of Fowler.
Sensational golf from Rickie Fowler, who makes it three birdies on the bounce with a three on the 12th and the lead is cut to one solitary shot.
McIlroy misses the fairway on the 12th and his second flies left and doesn't make the green. He's going to need to chip and sink in two to save par.
Jim Furyk fails to make par on the 14th and slips to seven under. He's not out of it but can now ill afford any more mistakes today.
Well, well, well. McIlroy produces a fine chip to leave himself a three footer for par and although his put flirts with the outside of the hole, it doesn't drop and that'a bogey five for the Irishman. He now shares the lead with Fowler at 12 under.
Par for Fowler on the 13th, ending his birdie barrage for now...
McIlroy holds his nerve with a seven footer on the 13th to save par. Dustin Johnson finally rustles up a birdie - his first since the opening hole - to go to seven under.
The ebb and flow continues. Fowler misses his longish par putt on the 14th and drops a shot.
Justin Rose cards a birdie on the 18th and finishes Day Three on three under, five under for the tournament. He's hardly snapping at the heels of the leaders but he's not completely out of contention yet.
Cracking putt on the 14th from Rory. A beautiful read of the green there and it's a birdie which takes him back to 13 under and two clear of Fowler.
Fowler misses a tricky birdie putt on the 15th and fails for now to make further inroads into McIlroy's advantage. The momentum has just swung in the Irishman's favour.
Sergio Garcia still a threat but the Spaniard might be a tad frustrated as he prepares to play the 16th considering he's had six pars on the bounce. In other news, Fowler finds the rough with his tee shot on the 16th.
McIlroy goes close with a monster putt for birdie on the 15th but has to settle for a par as it drifts inches wide of the hole.
Just like London buses, Johnson waits what seems like an eternity for a birdie and then two come along in successive holes as the Americans cards a two on the 15th to go eight under
Birdie from Victor Dubuisson on the last hole and it's been a cracking day for the Frenchman. He's four under for the round and eight under for the tournament and could be a name on everyone's lips tomorrow...